As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Sunday, 25 December 2016

New study doubles the estimate of bird species in the world

December 12, 2016

New research led by the American
Museum of Natural History suggests that there are about 18,000 bird species in
the world—nearly twice as many as previously thought. The work focuses on
"hidden" avian diversity—birds that look similar to one another, or
were thought to interbreed, but are actually different species. Recently
published in the journal PLOS ONE, the study has serious implications for
conservation practices.

"We are proposing a major
change to how we count diversity," said Joel Cracraft, an author of the
study and a curator in the American Museum of Natural History's Department of
Ornithology. "This new number says that we haven't been counting and
conserving species in the
ways we want."

Birds are traditionally thought
of as a well-studied group, with more than 95 percent of their global species
diversity estimated to have been described. Most checklists used by bird
watchers as well as by scientists say that there are roughly between 9,000 and
10,000 species of birds. But those numbers are based on what's known as the
"biological species concept," which defines species in terms of what
animals can breed together.

"It's really an outdated
point of view, and it's a concept that is hardly used in taxonomy outside of
birds," said lead author George Barrowclough, an associate curator in the
Museum's Department of Ornithology.

For the new work, Cracraft,
Barrowclough, and their colleagues at the University of Nebraska, Lincoln, and
the University of Washington examined a random sample of 200 bird species through
the lens of morphology—the study of the physical characteristics like plumage
pattern and color, which can be used to highlight birds with separate
evolutionary histories. This method turned up, on average, nearly two different
species for each of the 200 birds studied. This suggests that bird biodiversity
is severely underestimated, and is likely closer to 18,000 species worldwide.

The researchers also surveyed
existing genetic studies of birds, which revealed that there could be upwards
of 20,000 species. But because the birds in this
body of work were not selected randomly—and, in fact, many were likely chosen
for study because they were already thought to have interesting genetic
variation—this could be an overestimate. The authors argue that future taxonomy
efforts in ornithology should be based on both methods.